Silodosin has selective inhibition on the contraction of urethral smooth muscle and reduces the pressure in the urethra, but silodosin does not greatly influence on the blood pressure, thus it is used for treating benign prostatic hyperplasia.
As an efficient method of producing silodosin, the patent CN101993406 reports the following route:

The main defects of this route are that: 1. The yield of step c is low (33.4%), and ee value is not high (93.9%). 2. The yield of step d is low, and the by-product compound (8) is difficult to be removed in the purification process.

As another efficient method of producing silodosin, the patent WO2012062229 reports the following route:

to This route mainly has two defects: 1. The reaction paths are long. 2. The reaction yield of step a is low (44.8%), and column chromatography is required for purification.